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(N0 M W R, PATTERSON- ,MERGURY TERMINAL FOR TELEGRAPHYOABLES.

No. 245,972. A Patented Aug. 23,1881.

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Z06 Z2066 sea fivvemfor. 77 RQPditerspn UNITED STATES PATENT OFFICE.

WILLIAM R. PATTERSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WEST- ERNELECTRIC MANUFACTURING COMPANY, OF SAME PLACE.

MERCURY TERMINAL FOR TELEGRAPH-CABLES.

SPECIFICATION forming part of Letters Patent No. 245,972, dated August23, 1881.

I Application filed April 1, 1881. (N model.)

To all whom it may concern:

Be it known that 1, WILLIAM R.'PATTER- sort, of Chicago, Illinois, havediscovered certain new and useful Improvements in Mercury Terminals forTelegraph-Gables, of which the following is a full, clear, concise, andexact description.

In the class of cables to which myinvention relates the conductorsconsist of wires severally wound wit-h some fibrous material and bunchedand bound together by a strong serving. The core of conductors thusprepared is drawn within a metallic pipe. Some insulating substance,either solid, liquid, or gaseous, isintroduced into the pipe, whichfills the pores of the fibrous covering. When the insulating substanceis a solid, like paraffine-wax, the fibrous covering of the severalconductors may be omitted.

I will designate the pipe and cable of conductors properly laid as thecable, and will speak of the cable of insulated conductors as the core.

In the drawings, Figure lis an elevation of my terminal. Fig. 2 is adetail of a portion thereof. Fig. 3 represents a vertical section of anoil-cable and a modified form of terminal. Fig. 4=is the form ofbinding-post which I find most convenient.

Like letters indicate like parts.

In Fig. 1 two conductors, a, are shown bound together by serving 1). Themetallic pipe 0 is bent so as to connect with the U-shaped pipe d of theterminal. The core ordinarily approximately fills the pipe 0, and thepipe 01 is usually somewhat larger than pipe 0, in. order that there maybe room to splice the several conductors to their correspondinggutta-percha-covered or otherwise insulated wires 0. Mercury f isintroduced into the pipe, as shown, and rises and falls in response tothe pressure upon the gas or dry air within the pipe. The wires e arecovered with some impervious insulating material, and extend from wherethey are spliced with the conductors to through the mercury in pipe 01and project through the rubber cap 9, as shown. All the wires 0 may comethrough a single opening in the cap, in which case paraffihe-wax may beturned in at the opening around the wires, so as to keep them in place.

The glass tube h serves as a vent for the air when the mercury is actedupon by the pressure upon the gas or other substance of the cable. Theheight of the mercury may always be ascertained by observing theindicator 2', which may be graduated to indicate difi'erent degrees ofpressure. I have provided an automatic signaling device for givingnotice when the pressure falls below a certain limit.

70 is a wire insulated with gutta-percha, except at its extremities. Thelower end is adjusted so that it will not touch the mercury; but whenthe pressure is reduced the mercury will rise so as to touch the lowerend of the wire 70. By connecting a signal-bell and bat tery in aground-line connecting with the upper end of wire I: the decrease ofpressure beyond a fixed limit may thus be automatically indicated.

When oil is used in the cable an extra bend may be made in the cable inthe form of an inverted U, in order to keep the oil from com-' in g intodirect contact with the covering of the wires in the terminal. I

The terminal shown in Fig. 3 is useful when one or a small number ofwires are brought out at some point along the section of the cable.

The pipe 1 contains the core of conductors m.

The bushing n and hollow pin 0 are similar to the bushing and metallicpin described in my Patent No. 233,162, of October 12, 1880. The mercuryin pipe 1) protects the bushing from moisture, while the bushingprevents the transmission of pressure from the cable to the branch, andin case of injury to the branch protects the cable. Since there is nopressure from vent is not necessary.

The wire or wires q may be carried out in the manner indicated inFig. 1. When two or three conductors are brought out together I use,preferably, a rubber plug or plate, instead of the bushing, and screwinto holes provided in the plate as many metallic pins r (see Fig. 4) asthere are wires 8 to be brought out. The wire 8 is preferably broughtthrough the pin and its end bent, as shown at t, Fig. 4.. Thebindingpost i is then screwed onto the pin, so as to press firmlyagainst the bent end of the wire projecting through the pin.

the cable upon the mercury within pipe 19 the My invention has specialreference to telegraph-cables in which dry air or other gas, eithercirculating or under pressure, is used to protect theseverally-insulated conductors of the core, though it may be applied toany pipe telegraph-cable. WVhen oil is used the guttapcrcha-coveredwires of the terminal must be protected from the oil. This may be doneby an extra bend in the cable, near the terminal, as before indicated,so that capillary attraction will not draw the oil up to the splice,orin the manner indicated in Fig. 3. The mercury will efl'ectuallyprevent moisture from penetrating to the splice.

In case iron is used for the pipe of the terminal,it should beamalgamated on the inside, so as to come in more intimate contact withthe mercury.

The glass tube which forms the indicatori is of great advantage whenitis desired to maintain a substantially uniform pressure upon the gasor liquid of the cable.

The rise or fall of the mercury may be made to indicate the fact at theoffice by means of suitable circuits, or may be made to automaticallyestablish the pressure by connecting a tank previously charged, or bycausing the generation of carbonic-acid gas by allowing acid to run uponmarble-dust in a chamber connected with the cable.

The form of the bend in the terminal pipeis not essential, providedsufficient vertical space is allowed in the two legs for the mercury,and this depends upon the am ount of pressure within the cable.

The upper end of the outer branch of the terminal for a small number ofthe wires (shown in Fig. 3) may project above the surface of the groundor be so arranged that the wire or wires thereof may be accessible. Thepressure upon the fluid ot' the cable is not transmitted to the mercuryof the latter style of terminal, and therefore the mercury is at thesame level in both branches of the bent pipe, and the indieating andsignaling apparatus of the terminal shown in Fig. 1 cannot be used.

I claim- 1. The terminal consisting of a U-shaped pipe in combinationwith mercury, through which one or more conductors are run,substantially as and for the purpose specified.

2. The terminal consisting of U-shaped pipe and mercury in said pipe, incombination with a rubber plug, one or more electric conductors andhollow pins, one for each conductor, and binding-posts, one for eachhollowpin, substantially as and for the purpose specified.

3. The terminal consisting of pipe (1, wires 6, and mercuryf, incombination with a cable, substantially as and for the purposespecified.

WILLIAM R. PATTERSON.

WVitnesses:

. GEORGE P. BARTON,

VVILLIAM S. GRANGER.

